[Discussion] How to write a good capture?

Been looking for any discussion on this online and I've come back empty handed, so let's talk a bit! What do you think constitutes a good capture, and how can you write a Pokemon capture to feel natural and believable?
I'm currently writing part of my Pokemon fic that has the MC catch a Mankey which stole their food and has generally been harrasing them. The main issue is that MC would obviously have no desire to catch this Pokemon, given how much they've bothered them. So how could I take the story in a direction that leads to their capture?

In another, similar, line of thought, how often should a new Pokemon be caught? Do you think a full team should be assembled before the second gym, or should it take much longer?

Oh there's so much you can do with captures! They really don't have to be deliberate or thought through much at all inside the story. Accidental captures work just fine- my character's third capture was him trying to rescue his rapidly emptying backpack from a Skiddo, and he threw whatever was on hand to try and scare it away- oops, it was a PokéBall, and now he has a Skiddo! Or your Mankey can just as easily steal a PokéBall to investigate or for attention, and not try very hard to get out. Or you can go the route of your MC figuring out what this Pokémon needs- food? Companionship? Attention? And have them decide to provide that, as filling that need should lead to better behavior. That's pretty dependant on your character's personality and motivations though.

I generally say I prefer a slow team build, but I love to also put together a team of three pretty early and just spend a lot of time with them. I tend to even prefer to not ever have a full team. It just seems like so much to manage for a character, you know?

RP is a little different, 'cause you usually only can grab certain Pokémon when the GM allows for it. But, we can make it work well regardless! Casey picked up his starter and his first catch on his first day, with his third on the third, before any gyms. That was perfect for my preferences! Marie had four within a week as well, though she took on two gyms before her fourth. But that's where they hover- at the two week/third gym mark Casey will still not have any more, and Marie is coming up on three weeks/fifth gym and won't be catching anything else for a long time. She has a lot of work to do with her current team!

That's mostly what it's about to me, how much time and care and effort is put into the Pokémon and their development. The biggest reason I would feel like a character is catching Pokémon too quickly is if they were spending too little time working with those Pokémon. And I personally find it easier to keep captures limited and infrequent, so I can more easily make it feel like we are seeing the Pokémon enough. I've read some fics that do very well using Pokémon more as a backdrop and not focusing super much on them as characters, but that's not my style :)

I don't think there really is a right way to write captures. There's just too many different ways to achieve it. So long as there's a reason for your trainer to want to make the capture, it's probably the correct way. In the case of the troublesome Mankey, there's a few ways you can go. You could delay the capture and have your protag encounter the Mankey a few times and gradually develop a less antagonistic bond. This can allow you develop a really compelling Pokemon/trainer dynamic and gives both characters room to grow. You could have your trainer resolve to catch them to teach them some manners (or just assert dominance lol) this means you maintain the antagonistic relationship into their partnership and can watch is change into a more friendly one over time working together. You could also have it be accidental, but then you kinda have to double back to my previous suggestion or have your trainer go "well now you can't bother anyone else passing through" otherwise you're back to square one with "why would they hang onto this Pokemon they don't even want?"

As for when to handle captures, I think slower-paced works better. I wouldn't put a gym-milestone based system into effect necessarily, at least I won't comment on one because I don't know how spread out your gym battles will be. But definitely take it slower, there's no need to rush to a full team. Taking your time gives you more room to explore the personalities of the Pokemon and how their relationships with each other and their trainer. It means you can treat them as characters instead of props.